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2.
World Neurosurg ; 130: e941-e952, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31302278

RESUMO

BACKGROUND: Poorly understood cranial fluid accumulations are frequently observed after decompressive craniectomy and often termed "external hydrocephalus." These findings are difficult to explain using traditional models of hydrocephalus. METHODS: Representative cases, clinical management, and literature overview are presented. RESULTS: We present a hypothesis that abnormal cranial fluid accumulations develop after decompressive craniectomy in a vulnerable subset of patients as a result of 1) the large compliant cranial defect with durotomy causing reduced internal brain expansion, ventricular squeezing, and pulsatile cerebrospinal fluid (CSF) circulation; 2) impaired pulsatile CSF flow along major cerebral arteries and the adjoining perivascular spaces (Virchow-Robin spaces); 3) reduced clearance of interstitial fluid by the glymphatic system; and 4) redistribution of CSF from the subarachnoid space into the subdural and subgaleal compartments and the ventricles. CONCLUSION: Closure of the cranial defect with cranioplasty improves cerebral blood flow and CSF pulsatile circulation and is frequently sufficient to resolve the external hydrocephalus.


Assuntos
Líquido Cefalorraquidiano , Craniectomia Descompressiva/efeitos adversos , Sistema Glinfático/diagnóstico por imagem , Hemodinâmica , Hidrocefalia/diagnóstico por imagem , Linfangioma Cístico/diagnóstico por imagem , Adulto , Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Líquido Cefalorraquidiano/fisiologia , Craniectomia Descompressiva/tendências , Feminino , Sistema Glinfático/fisiologia , Hemodinâmica/fisiologia , Humanos , Hidrocefalia/etiologia , Hidrocefalia/fisiopatologia , Hidrodinâmica , Linfangioma Cístico/etiologia , Linfangioma Cístico/fisiopatologia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/fisiopatologia
3.
Fluids Barriers CNS ; 16(1): 19, 2019 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-31217012

RESUMO

BACKGROUND: Periarterial spaces (PASs) are annular channels that surround arteries in the brain and contain cerebrospinal fluid (CSF): a flow of CSF in these channels is thought to be an important part of the brain's system for clearing metabolic wastes. In vivo observations reveal that they are not concentric, circular annuli, however: the outer boundaries are often oblate, and the arteries that form the inner boundaries are often offset from the central axis. METHODS: We model PAS cross-sections as circles surrounded by ellipses and vary the radii of the circles, major and minor axes of the ellipses, and two-dimensional eccentricities of the circles with respect to the ellipses. For each shape, we solve the governing Navier-Stokes equation to determine the velocity profile for steady laminar flow and then compute the corresponding hydraulic resistance. RESULTS: We find that the observed shapes of PASs have lower hydraulic resistance than concentric, circular annuli of the same size, and therefore allow faster, more efficient flow of cerebrospinal fluid. We find that the minimum hydraulic resistance (and therefore maximum flow rate) for a given PAS cross-sectional area occurs when the ellipse is elongated and intersects the circle, dividing the PAS into two lobes, as is common around pial arteries. We also find that if both the inner and outer boundaries are nearly circular, the minimum hydraulic resistance occurs when the eccentricity is large, as is common around penetrating arteries. CONCLUSIONS: The concentric circular annulus assumed in recent studies is not a good model of the shape of actual PASs observed in vivo, and it greatly overestimates the hydraulic resistance of the PAS. Our parameterization can be used to incorporate more realistic resistances into hydraulic network models of flow of cerebrospinal fluid in the brain. Our results demonstrate that actual shapes observed in vivo are nearly optimal, in the sense of offering the least hydraulic resistance. This optimization may well represent an evolutionary adaptation that maximizes clearance of metabolic waste from the brain.


Assuntos
Artérias Cerebrais/fisiologia , Líquido Cefalorraquidiano/fisiologia , Sistema Glinfático/fisiologia , Modelos Biológicos , Pia-Máter/fisiologia , Encéfalo/irrigação sanguínea , Encéfalo/fisiologia , Humanos , Pia-Máter/irrigação sanguínea
4.
Invest Ophthalmol Vis Sci ; 60(7): 2773-2780, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31247084

RESUMO

Purpose: Explore in vivo whether there is direct communication between the cerebrospinal fluid (CSF) and extravascular compartment of human visual pathway structures. Methods: A prospective and observational study included 10 subjects who underwent intrathecal gadolinium-enhanced magnetic resonance imaging (MRI) for suspected CSF circulation disorder, but with a negative result and with no known ophthalmic diseases. After precontrast T1-weighted MRI, 0.5 mL of gadobutrol (Gadovist, 1.0 mmol/mL) was injected intrathecally. Gadobutrol distributes in the extravascular space, and served as a CSF tracer. Consecutive MRI scans were obtained throughout 24 to 48 hours. To assess gadobutrol contrast enrichment, regions of interest (ROIs) were placed at multiple locations along the visual pathway, from the primary visual cortex to the eye's vitreous body. CSF tracer dependent T1 signal was measured in each ROI. A linear mixed-model was used for statistical analyses. Results: CSF tracer enrichment was found within the optic nerve, optic chiasm, optic tract, and primary visual cortex (P < 0.001). Peak tracer enrichment in the visual pathway generally occurred after 24 hours and was preceded by peak enhancement in the prechiasmatic cistern after 4 to 6 hours. Conclusions: The results indicate direct communication between CSF of subarachnoid space and the extravascular space of the human visual pathway. Extravascular entry of the CSF tracer is a prerequisite for a glymphatic system, the present findings may suggest its presence. The existence of a glymphatic system in the human visual pathway could bring novel perspectives on the pathophysiology and treatment of ophthalmic diseases.


Assuntos
Espaço Subaracnóideo/fisiologia , Vias Visuais/fisiologia , Adulto , Líquido Cefalorraquidiano/fisiologia , Meios de Contraste/administração & dosagem , Feminino , Sistema Glinfático/fisiologia , Humanos , Injeções Espinhais , Imagem por Ressonância Magnética , Masculino , Quiasma Óptico/diagnóstico por imagem , Quiasma Óptico/fisiologia , Nervo Óptico/diagnóstico por imagem , Nervo Óptico/fisiologia , Trato Óptico/diagnóstico por imagem , Trato Óptico/fisiologia , Compostos Organometálicos/administração & dosagem , Estudos Prospectivos , Espaço Subaracnóideo/diagnóstico por imagem , Córtex Visual/diagnóstico por imagem , Córtex Visual/fisiologia , Vias Visuais/diagnóstico por imagem
5.
Neurol Med Chir (Tokyo) ; 59(7): 271-280, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31068544

RESUMO

It is known that the cerebrospinal fluid (CSF) pulsation flow sign in the lateral ventricles directly above the foramen of Monro (CPF-M) on axial fluid attenuated inversion recovery (FLAIR) is a normal physiological finding as an artifact of FLAIR. In this study, whether CPF-M can be used as a neuroradiological finding related to pathological conditions in patients with acute aneurysmal subarachnoid hemorrhage (aSAH) was investigated. CPF-M-related clinical features were retrospectively evaluated in 147 aSAH patients who underwent adequate serial MRI examinations without massive intraventricular hemorrhage (IVH) of the lateral ventricle within 48 h of ictus. The frequency of the CPF-M in the control group was 32% (57/178), 33% (40/123), and 38% (45/117) for the normal control, chronic cerebral infarction, and deep white matter lesion (WML) groups, respectively. In aSAH patients, the overall prevalence of the CPF-M was 57% (84/147), significantly higher than in the three control groups. Multivariate analysis showed that age <70 years, lower IVH Hijdra score of the fourth ventricle, absence of T1-FLAIR mismatch, deep WMLs, old infarction, diffuse brain swelling, symptomatic delayed cerebral ischemia (DCI), shunt-dependent chronic hydrocephalus (SDCH), and favorable outcome were significantly associated with the CPF-M. Although limited to SAH patients without massive IVH of the lateral ventricles, one can conclude that, in acute aSAH, the presence of CPF-M on admission MRI suggests that the circulatory dynamics of the CSF from the basal cistern to the ventricles are approximately normal. Thus, this finding may appear to offer an indicator of a good outcome without DCI and SDCH.


Assuntos
Ventrículos Cerebrais/diagnóstico por imagem , Ventrículos Cerebrais/fisiopatologia , Líquido Cefalorraquidiano/fisiologia , Fluxo Pulsátil/fisiologia , Hemorragia Subaracnóidea/diagnóstico por imagem , Hemorragia Subaracnóidea/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Hemorragia Subaracnóidea/cirurgia , Resultado do Tratamento
6.
Math Biosci Eng ; 16(4): 2811-2851, 2019 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-31137239

RESUMO

In this paper we provide the numerical simulations of two cerebrospinal fluid dynamics models by comparing our results with the real data available in literature (see Section 4). The models describe different processes in the cerebrospinal fluid dynamics: the cerebrospinal flow in the ventricles of the brain and the reabsorption of the fluid. In the appendix we show in detail the mathematical analysis of both models and we identify the set of initial conditions for which the solutions of the systems of equations do not exhibit blow up. We investigate step by step the accuracy of these theoretical outcomes with respect to the real cerebrospinal physiology and dynamics. The plan of the paper is provided in Section 1.5.


Assuntos
Encéfalo/fisiologia , Líquido Cefalorraquidiano/fisiologia , Modelos Biológicos , Algoritmos , Animais , Ventrículos Cerebrais/fisiologia , Plexo Corióideo/fisiologia , Simulação por Computador , Humanos , Pressão Intracraniana
7.
Fluids Barriers CNS ; 16(1): 11, 2019 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-31039805

RESUMO

BACKGROUND: Fluid dynamics of the craniospinal system are complex and still not completely understood. In vivo flow and pressure measurements of the cerebrospinal fluid (CSF) are limited. Whereas in silico modeling can be an adequate pathway for parameter studies, in vitro modeling of the craniospinal system is essential for testing and evaluation of therapeutic measures associated with innovative implants relating to, for example, normal pressure hydrocephalus and other fluid disorders. Previously-reported in vitro models focused on the investigation of only one hypothesis of the fluid dynamics rather than developing a modular set-up to allow changes in focus of the investigation. The aim of this study is to present an enhanced and validated in vitro model of the CSF system which enables the future embedding of implants, the validation of in silico models or phase-contrast magnetic resonance imaging (PC-MRI) measurements and a variety of sensitivity analyses regarding pathological behavior, such as reduced CSF compliances, higher resistances or altered blood dynamics. METHODS: The in vitro model consists of a ventricular system which is connected via the aqueduct to the cranial and spinal subarachnoid spaces. Two compliance chambers are integrated to cushion the arteriovenous blood flow generated by a cam plate unit enabling the modeling of patient specific flow dynamics. The CSF dynamics are monitored using three cranial pressure sensors and a spinal ultrasound flow meter. Measurements of the in vitro spinal flow were compared to cervical flow data recorded with PC-MRI from nine healthy young volunteers, and pressure measurements were compared to the literature values reported for intracranial pressure (ICP) to validate the newly developed in vitro model. RESULTS: The maximum spinal CSF flow recorded in the in vitro simulation was 133.60 ml/min in the caudal direction and 68.01 ml/min in the cranial direction, whereas the PC-MRI flow data of the subjects showed 122.82 ml/min in the caudal and 77.86 ml/min in the cranial direction. In addition, the mean ICP (in vitro) was 12.68 mmHg and the pressure wave amplitude, 4.86 mmHg, which is in the physiological range. CONCLUSIONS: The in vitro pressure values were in the physiological range. The amplitudes of the flow results were in good agreement with PC-MRI data of young and healthy volunteers. However, the maximum cranial flow in the in vitro model occurred earlier than in the PC-MRI data, which might be due to a lack of an in vitro dynamic compliance. Implementing dynamic compliances and related sensitivity analyses are major aspects of our ongoing research.


Assuntos
Líquido Cefalorraquidiano/fisiologia , Hidrodinâmica , Modelos Biológicos , Fluxo Pulsátil/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia , Aqueduto do Mesencéfalo/fisiologia , Ventrículos Cerebrais/fisiologia , Humanos
8.
PLoS Biol ; 17(4): e3000235, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-31002663

RESUMO

Multiple types of microvilliated sensory cells exhibit an apical extension thought to be instrumental in the detection of sensory cues. The investigation of the mechanisms underlying morphogenesis of sensory apparatus is critical to understand the biology of sensation. Most of what we currently know comes from the study of the hair bundle of the inner ear sensory cells, but morphogenesis and function of other sensory microvilliated apical extensions remain poorly understood. We focused on spinal sensory neurons that contact the cerebrospinal fluid (CSF) through the projection of a microvilliated apical process in the central canal, referred to as cerebrospinal fluid-contacting neurons (CSF-cNs). CSF-cNs respond to pH and osmolarity changes as well as mechanical stimuli associated with changes of flow and tail bending. In vivo time-lapse imaging in zebrafish embryos revealed that CSF-cNs are atypical neurons that do not lose their apical attachment and form a ring of actin at the apical junctional complexes (AJCs) that they retain during differentiation. We show that the actin-based protrusions constituting the microvilliated apical extension arise and elongate from this ring of actin, and we identify candidate molecular factors underlying every step of CSF-cN morphogenesis. We demonstrate that Crumbs 1 (Crb1), Myosin 3b (Myo3b), and Espin orchestrate the morphogenesis of CSF-cN apical extension. Using calcium imaging in crb1 and espin mutants, we further show that the size of the apical extension modulates the amplitude of CSF-cN sensory response to bending of the spinal cord. Based on our results, we propose that the apical actin ring could be a common site of initiation of actin-based protrusions in microvilliated sensory cells. Furthermore, our work provides a set of actors underlying actin-based protrusion elongation shared by different sensory cell types and highlights the critical role of the apical extension shape in sensory detection.


Assuntos
Mecanotransdução Celular/fisiologia , Microvilosidades/fisiologia , Células Receptoras Sensoriais/fisiologia , Actinas/metabolismo , Animais , Diferenciação Celular , Extensões da Superfície Celular/fisiologia , Líquido Cefalorraquidiano/fisiologia , Morfogênese/fisiologia , Neurônios/fisiologia , Medula Espinal/metabolismo , Peixe-Zebra/metabolismo
9.
Neurol Med Chir (Tokyo) ; 59(4): 133-146, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30814424

RESUMO

The "cerebrospinal fluid (CSF) circulation theory" of CSF flowing unidirectionally and circulating through the ventricles and subarachnoid space in a downward or upward fashion has been widely recognized. In this review, observations of CSF motion using different magnetic resonance imaging (MRI) techniques are described, findings that are shared among these techniques are extracted, and CSF motion, as we currently understand it based on the results from the quantitative analysis of CSF motion, is discussed, along with a discussion of slower water molecule motion in the perivascular, paravascular, and brain parenchyma. Today, a shared consensus regarding CSF motion is being formed, as follows: CSF motion is not a circulatory flow, but a combination of various directions of flow in the ventricles and subarachnoid space, and the acceleration of CSF motion differs depending on the CSF space. It is now necessary to revise the currently held concept that CSF flows unidirectionally. Currently, water molecule motion in the order of centimeters per second can be detected with various MRI techniques. Thus, we need new MRI techniques with high-velocity sensitivity, such as in the order of 10 µm/s, to determine water molecule movement in the vessel wall, paravascular space, and brain parenchyma. In this paper, the authors review the previous and current concepts of CSF motion in the central nervous system using various MRI techniques.


Assuntos
Ventrículos Cerebrais/diagnóstico por imagem , Líquido Cefalorraquidiano/fisiologia , Hidrodinâmica , Imagem por Ressonância Magnética , Espaço Subaracnóideo/diagnóstico por imagem , Ventrículos Cerebrais/fisiopatologia , Humanos , Espaço Subaracnóideo/fisiopatologia
10.
Diagn Interv Radiol ; 25(2): 144-156, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30774095

RESUMO

There are many differences in fluoroscopy-guided lumbar puncture (FG-LP) technique among radiologists. Even within the same institution, there are a variety of preferences among proceduralists with individual perspectives based on the literature, training, and/or experience. Our aim is to provide familiarity with various techniques involved in FG-LP and provide insight on how to improve patient outcomes. The pertinent anatomy and physiology, indications, contraindications, patient management, complications of the procedure, and procedural techniques for performing an FG-LP are reviewed in detail. Potentially controversial topics regarding FG-LP are also addressed. There are many differences in fluoroscopy-guided lumbar puncture (FG-LP) technique among radiologists (1). Even within the same institution, there are a variety of individual preferences among physicians with different perspectives based on a combination of literature familiarity, training, and personal experience. Our aim is to provide familiarity with various techniques involved in FG-LP, improve efficiency, and improve patient outcomes. We will also address possible controversial issues regarding FG-LPs using an evidence-based approach.


Assuntos
Fluoroscopia/métodos , Radiologistas/estatística & dados numéricos , Punção Espinal/métodos , Anatomia , Líquido Cefalorraquidiano/fisiologia , Feminino , Humanos , Pressão Intracraniana/fisiologia , Masculino , Agulhas , Cefaleia Pós-Punção Dural/epidemiologia , Radiologia Intervencionista , Punção Espinal/efeitos adversos , Adulto Jovem
12.
Curr Biol ; 29(2): 229-241.e6, 2019 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-30612902

RESUMO

Motile cilia are miniature, propeller-like extensions, emanating from many cell types across the body. Their coordinated beating generates a directional fluid flow, which is essential for various biological processes, from respiration to reproduction. In the nervous system, ependymal cells extend their motile cilia into the brain ventricles and contribute to cerebrospinal fluid (CSF) flow. Although motile cilia are not the only contributors to CSF flow, their functioning is crucial, as patients with motile cilia defects develop clinical features, like hydrocephalus and scoliosis. CSF flow was suggested to primarily deliver nutrients and remove waste, but recent studies emphasized its role in brain development and function. Nevertheless, it remains poorly understood how ciliary beating generates and organizes CSF flow to fulfill these roles. Here, we study motile cilia and CSF flow in the brain ventricles of larval zebrafish. We identified that different populations of motile ciliated cells are spatially organized and generate a directional CSF flow powered by ciliary beating. Our investigations revealed that CSF flow is confined within individual ventricular cavities, with little exchange of fluid between ventricles, despite a pulsatile CSF displacement caused by the heartbeat. Interestingly, our results showed that the ventricular boundaries supporting this compartmentalized CSF flow are abolished during bodily movement, highlighting that multiple physiological processes regulate the hydrodynamics of CSF flow. Finally, we showed that perturbing cilia reduces hydrodynamic coupling between the brain ventricles and disrupts ventricular development. We propose that motile-cilia-generated flow is crucial in regulating the distribution of CSF within and across brain ventricles.


Assuntos
Encéfalo/fisiologia , Ventrículos Cerebrais/crescimento & desenvolvimento , Líquido Cefalorraquidiano/fisiologia , Cílios/metabolismo , Peixe-Zebra/fisiologia , Animais , Peixe-Zebra/crescimento & desenvolvimento
13.
Magn Reson Med ; 81(1): 331-341, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30194785

RESUMO

PURPOSE: To evaluate the visualization of CSF dynamics using the novel method multi-spin echo acquisition cine imaging (MUSACI). METHODS: MUSACI is based on multi-echo volume isotropic turbo spin-echo acquisition (VISTA) with pulse gating. MUSACI images were acquired in 11 healthy volunteers (7 men, 4 women; age range, 24-46 y, mean age, 31.9 ± 5.51 y). We compared the CSF signal intensities (SIs) at multiple values of the effective echo time (TEeff ) at the lateral ventricle, the foramen of Monro, the third ventricle, and the fourth ventricle. We compared the CSF SI changes in MUSACI at multiple TEeff and the mean velocities in phase contrast (PC) at each trigger delay at the foramen of Monro, the third ventricle, and the fourth ventricle. RESULTS: The anterograde CSF motion from the aqueduct to the fourth ventricle, the retrograde motion from the aqueduct to the third ventricle, and the retrograde motion from the foramen of Monro to the lateral ventricle were observed with MUSACI. The CSF SIs at each TEeff in the foramen of Monro, the third ventricle, and the fourth ventricle were significantly lower than that at each TEeff in the lateral ventricle (P < 0.05). The CSF SI in MUSACI changed with the TEeff , and the CSF movements were observed at each trigger delay in PC. CONCLUSION: MUSACI can provide both high-resolution anatomical detail of the CSF passageways and physiologic information regarding CSF dynamics in a single scan.


Assuntos
Ventrículos Cerebrais/diagnóstico por imagem , Líquido Cefalorraquidiano/diagnóstico por imagem , Imagem Cinética por Ressonância Magnética , Imagem por Ressonância Magnética , Adulto , Líquido Cefalorraquidiano/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Hidrocefalia/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Movimento (Física) , Imagens de Fantasmas
14.
Gen Thorac Cardiovasc Surg ; 67(1): 180-186, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30187260

RESUMO

OBJECTIVE: To prevent paraplegia in patients undergoing thoracoabdominal aortic aneurysm repair, the importance of preoperative identification of the Adamkiewicz artery and reconstruction of critical intercostal artery have been advocated. Conversely, significance of collateral network for spinal cord perfusion has been recognized. We invented a new system consisting of a direct monitoring of cerebrospinal fluid temperature (CSFT) and differential selective hypothermic intercostal artery perfusion (D-HIAP). METHODS: After exposing a critical intercostal artery, a 10-mm prosthetic graft was anastomosed in an end to side fashion. A balloon-tipped catheter was inserted into the graft to perfuse with 15 °C blood. Neighboring intercostal arteries were also perfused in the same fashion. Serial monitoring of CSFT was performed. Between January 2011 and January 2015, D-HIAP was employed in 50 patients with Adamkiewicz artery that located within a reconstructed area. RESULTS: Significant CSFT drop was recorded after initiation of D-HIAP in 42 (84%) patients. Of those, 34 (68%) patients showed significantly lowered CSFT with D-HIAP into a single critical intercostal artery. Perfusion into plural intercostal arteries was necessary for CSFT drop in 2 cases (4%), and plural intercostal artery perfusion further enhanced CSFT drop that had been modestly achieved by single intercostal artery perfusion in 6 cases (12%). Eight (16%) patients did not exhibit a significant drop in CSFT even when D-HIAP was employed for the critical and neighboring intercostal arteries. CONCLUSIONS: The detection of a disparity in temperature between the intrathecal space and blood generated by D-HIAP revealed individual variability in CSFT changes, which may imply a complexity in spinal cord perfusion. Intraoperative D-HIAP may help to identify a major blood supply for spinal cord perfusion and underlying collateral network.


Assuntos
Aneurisma da Aorta Abdominal/cirurgia , Aneurisma da Aorta Torácica/cirurgia , Parada Circulatória Induzida por Hipotermia Profunda , Paraplegia/prevenção & controle , Procedimentos Cirúrgicos Reconstrutivos , Isquemia do Cordão Espinal/prevenção & controle , Procedimentos Cirúrgicos Vasculares/métodos , Temperatura Corporal , Líquido Cefalorraquidiano/fisiologia , Humanos , Músculos Intercostais/irrigação sanguínea , Perfusão/métodos , Tomografia Computadorizada por Raios X
15.
Acta Neurochir (Wien) ; 161(2): 247-256, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30443816

RESUMO

BACKGROUND: Net cerebrospinal fluid (CSF) flow within the cerebral aqueduct is usually considered to be antegrade, i.e., from the third to the fourth ventricle with volumes ranging between 500 and 600 ml over 24 h. Knowledge of individual CSF flow dynamics, however, is hitherto scarcely investigated. In order to explore individual CSF flow rate and direction, we assessed net aqueductal CSF flow in individuals with intracranial aneurysms with or without a previous subarachnoid hemorrhage (SAH). METHODS: A prospective observational study was performed utilizing phase-contrast magnetic resonance imaging (PC-MRI) to determine the magnitude and direction of aqueductal CSF flow with an in-depth, pixel-by-pixel approach. Estimation of net flow was used to calculate CSF flow volumes over 24 h. PC-MRI provides positive values when flow is retrograde. RESULTS: The study included eight patients with intracranial aneurysms. Four were examined within days after their SAH; three were studied in the chronic stage after SAH while one patient had an unruptured intracranial aneurysm. There was a vast variation in magnitude and direction of aqueductal CSF flow between individuals. Net aqueductal CSF flow was retrograde, i.e., directed towards the third ventricle in 5/8 individuals. For the entire patient cohort, the estimated net aqueductal CSF volumetric flow rate (independent of direction) was median 898 ml/24 h (ranges 69 ml/24 h to 12.9 l/24 h). One of the two individuals who had a very high estimated net aqueductal CSF volumetric flow rate, 8.7 l/24 h retrograde, later needed a permanent CSF shunt. CONCLUSIONS: The magnitude and direction of net aqueductal CSF flow vary extensively in patients with intracranial aneurysms. Following SAH, PC-MRI may offer the possibility to perform individualized assessments of the CSF circulation.


Assuntos
Aqueduto do Mesencéfalo/diagnóstico por imagem , Líquido Cefalorraquidiano/fisiologia , Aneurisma Intracraniano/diagnóstico por imagem , Hemorragia Subaracnóidea/diagnóstico por imagem , Adulto , Feminino , Humanos , Aneurisma Intracraniano/complicações , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Hemorragia Subaracnóidea/complicações
16.
Jpn J Radiol ; 37(2): 135-144, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30406868

RESUMO

PURPOSE: We aimed to investigate whether low b value diffusion-weighted imaging (DWI) can show the change of cerebrospinal fluid (CSF) dynamics. MATERIALS AND METHODS: The subjects of this retrospective study consisted of patients with ventricular dilatation (n = 50) and controls (n = 50). The CSF signal intensity on the b = 500 s/mm2 DWI was evaluated by a scoring method in the lateral, 3rd and 4th ventricles, the cerebral sulci and the Sylvian fissure. The signal void findings adjacent to the septum pellucidum were also evaluated. RESULTS: The CSF signal intensities were significantly less in lateral ventricle and 3rd ventricle of the ventricular dilatation subjects. In controls, the score for the signal void in the Sylvian fissure showed a significant positive correlation with age. However, other areas did not show a significant correlation with age. The appearance of the characteristic signal void adjacent to the septum pellucidum showed a significant correlation with ventricular dilatation. CONCLUSION: Our current study suggests that the CSF signal intensity on the b = 500 s/mm2 DWI may show the changes in CSF dynamics and might be useful to evaluate the overlook of CSF dynamics.


Assuntos
Líquido Cefalorraquidiano/diagnóstico por imagem , Líquido Cefalorraquidiano/fisiologia , Imagem de Difusão por Ressonância Magnética/métodos , Processamento de Imagem Assistida por Computador/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/diagnóstico por imagem , Criança , Pré-Escolar , Feminino , Hemodinâmica , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
17.
Magn Reson Med Sci ; 18(2): 163-169, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30393275

RESUMO

PURPOSE: It has been reported that intravenously administered gadolinium-based contrast agents (IV-GBCAs) leak into the cerebrospinal fluid (CSF) even in healthy subjects. The purpose of this study was to evaluate GBCA leakage from the cortical veins in patients with delayed imaging after IV-GBCA. MATERIALS AND METHODS: There are two parts of retrospective study. In the first part, we reviewed six patients with suspected endolymphatic hydrops (EH) who received a single dose of IV-GBCA (37-58 years old). The 3D-real inversion recovery images were obtained prior to the contrast administration as well as 5 min and 4 h after IV-GBCA. Leakage from the cortical veins to the CSF was graded as positive if enhancement around the cortical veins at 5 min was observed and had further spread into the CSF at 4 h after IV-GBCA.In the second part of this study, we reviewed 21 patients with suspected EH (17-69 years old). Images were obtained only at 4 h after IV-GBCA. The number of slices (NOS) with a positive GBCA leakage from the cortical veins was counted. The correlation of the NOS with age, gender, and degree of EH was evaluated by Spearman's rank correlation coefficient. RESULTS: In the first part of the study, the GBCA leakage from the cortical veins was positive in all patients. In the second part of the study, the GBCA leakage from the cortical veins was seen in all older patients (above 37 years old), but not in the five younger patients (younger than 37 years old). The NOS correlated significantly only with age (r = 0.755, P < 0.01), but not with gender or degree of EH. CONCLUSION: IV-GBCA leaks from the cortical veins into the surrounding CSF. The leakiness of the cortical veins significantly correlated with age, but not with gender or degree of EH.


Assuntos
Encéfalo/diagnóstico por imagem , Líquido Cefalorraquidiano/fisiologia , Meios de Contraste/administração & dosagem , Hidropisia Endolinfática/diagnóstico por imagem , Gadolínio/administração & dosagem , Imagem por Ressonância Magnética/métodos , Administração Intravenosa , Adolescente , Adulto , Idoso , Feminino , Voluntários Saudáveis , Humanos , Imagem Tridimensional/métodos , Injeções Intravenosas , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
18.
Nat Commun ; 9(1): 4878, 2018 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-30451853

RESUMO

Flow of cerebrospinal fluid (CSF) through perivascular spaces (PVSs) in the brain is important for clearance of metabolic waste. Arterial pulsations are thought to drive flow, but this has never been quantitatively shown. We used particle tracking to quantify CSF flow velocities in PVSs of live mice. CSF flow is pulsatile and driven primarily by the cardiac cycle. The speed of the arterial wall matches that of the CSF, suggesting arterial wall motion is the principal driving mechanism, via a process known as perivascular pumping. Increasing blood pressure leaves the artery diameter unchanged but changes the pulsations of the arterial wall, increasing backflow and thereby reducing net flow in the PVS. Perfusion-fixation alters the normal flow direction and causes a 10-fold reduction in PVS size. We conclude that particle tracking velocimetry enables the study of CSF flow in unprecedented detail and that studying the PVS in vivo avoids fixation artifacts.


Assuntos
Artérias/diagnóstico por imagem , Líquido Cefalorraquidiano/diagnóstico por imagem , Cisterna Magna/diagnóstico por imagem , Sistema Glinfático/diagnóstico por imagem , Análise de Onda de Pulso/métodos , Animais , Artérias/fisiologia , Líquido Cefalorraquidiano/fisiologia , Cisterna Magna/anatomia & histologia , Cisterna Magna/fisiologia , Corantes Fluorescentes/química , Sistema Glinfático/anatomia & histologia , Sistema Glinfático/fisiologia , Frequência Cardíaca/fisiologia , Processamento de Imagem Assistida por Computador , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal , Microscopia de Fluorescência por Excitação Multifotônica/instrumentação , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Microesferas , Tamanho da Partícula , Fluxo Pulsátil/fisiologia , Análise de Onda de Pulso/instrumentação , Reologia/instrumentação , Reologia/métodos
19.
Nat Genet ; 50(12): 1666-1673, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30420648

RESUMO

Straightening of the body axis is a major morphogenetic event that produces the typical head-to-tail shape of the vertebrate embryo. Defects in axial straightening can lead to debilitating disorders such as idiopathic scoliosis, characterized by three-dimensional curvatures of the spine1. Although abnormal cerebrospinal fluid (CSF) flow has been implicated in the development of idiopathic scoliosis2, the molecular mechanisms operating downstream of CSF flow remain obscure. Here we show that, in zebrafish embryos, cilia-driven CSF flow transports adrenergic signals that induce urotensin neuropeptides in CSF-contacting neurons along the spinal cord. Urotensins activate their receptor on slow-twitch muscle fibers of the dorsal somite; the contraction of these fibers likely results in straightening of the body axis. Consistent with this, mutation of the urotensin receptor resulted in severe scoliosis in adult zebrafish, closely mimicking the human disorder. These findings suggest that disruption of urotensin signaling by impaired CSF flow could be a critical etiological factor underlying the pathology of idiopathic scoliosis.


Assuntos
Líquido Cefalorraquidiano/fisiologia , Cílios/fisiologia , Urotensinas/genética , Animais , Animais Geneticamente Modificados , Padronização Corporal , Embrião não Mamífero , Regulação da Expressão Gênica no Desenvolvimento , Morfogênese/fisiologia , Neuropeptídeos/genética , Transdução de Sinais/genética , Medula Espinal/embriologia , Vertebrados/embriologia , Peixe-Zebra/embriologia , Peixe-Zebra/genética
20.
Nursing ; 48(12): 20-26, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30383569

RESUMO

A ventriculoperitoneal shunt (VPS) is the most common type of implanted cerebrospinal fluid shunt system. Nurses may care for patients who have undergone shunt placement or revision. This article discusses the indications for VPS placement in adults, possible complications, and nursing care for patients following a shunt placement procedure.


Assuntos
Derivação Ventriculoperitoneal/enfermagem , Adulto , Líquido Cefalorraquidiano/fisiologia , Humanos , Alta do Paciente , Educação de Pacientes como Assunto , Derivação Ventriculoperitoneal/efeitos adversos
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